Vaccinating humanitarian workers against COVID-19

Abstract Objective To describe the United Nations’ (UN’s) coronavirus disease 2019 (COVID-19) vaccination programme and its efforts to vaccinate frontline humanitarian personnel stationed in locations where access to COVID-19 vaccine was limited or absent. Methods The vaccination programme was structured as a two-level operation: a global vaccine deployment support team and local vaccine deployment teams in each participating country, territory or administrative area. The central group, led by a global vaccine coordinator, oversaw medical, legal, financial, logistical, data, technological and communication aspects. Local vaccine deployment teams were led by coordinators who managed registration, logistics, communication and vaccine administration. The programme used World Health Organization-approved COVID-19 vaccines and developed prioritization criteria for distributing vaccine supplies. The programme ensured that vaccines for the UN personnel were not diverted from the populations they were intended to serve. Findings The programme successfully formed 120 deployment teams across 152 eligible countries, territories and administrative areas, targeting approximately 673 000 individuals. By April 2023, 72 countries, territories and administrative areas had received over 470 000 doses, of which 337 072 doses were administered. Almost half of the doses administered (167 616) were to individuals in five UN hardship countries. Ninety-five severe adverse events were reported, but none led to any reported medical evacuation, permanent disability or death. Conclusion The programme demonstrated effective global coordination and local implementation, adapting to diverse contexts and operational challenges. The model can serve as a guide for global actors for future health emergencies, or for deploying health aid at a regional or global scale.


Introduction
The humanitarian workforce has been at the forefront of many, often concurrent crises, exposed to health and safety risks arising from their operations.These operations serve beneficiaries facing conflict, economic, social and climate crises, and recently the coronavirus disease 2019 (COVID- 19)  pandemic. 13][4] Among protection measures against biological risks, vaccination has long been a recognized cost-effective prevention tool, 5 typically administered before deployment to field missions, or at the occasion of local vaccination campaigns, such as against seasonal influenza.However, at the initial rollout of COVID-19 vaccines, organizations had limited access to vaccines where the humanitarian workers were operating due to the unequal global vaccine distribution. 6,7][10] The aim of the programme was to procure, deliver and administer vaccines where access to vaccines was limited or completely absent to UN humanitarian workers, peacekeepers, retired staff as well as individuals working for associated nongovernmental implementation partners. 11The programme was intended to enable humanitarian personnel to stay and deliver on critical mandates, and to contribute to ongoing recovery work from the pandemic.Here we describe the programme, the lessons learnt and success factors for application to future pandemics.

Vaccination programme design
The UN developed the vaccination programme as a twolevel operation to best support its global scope of work.The programme's published framework describes the overall programme set-up. 12t the central level, a cross-functional and inter-entity UN working group, known as the global vaccine deployment support team, was established.The group, which met through virtual meetings, was led by a global vaccine coordinator overseeing all functions of the programme, including medical, legal, financial, logistical, data, technological and communication aspects.The central support team contracted a global freight forwarding company, based in Denmark, to coordinate all vaccine shipments.
At the local level, each participating UN country team was invited by the central support team to set up a local vaccine deployment team led by a coordinator overseeing all local functions.The UN country teams appointed local vaccine deployment coordinators from different participating UN entities, based on the coordinators' respective expertise and availability. 13The coordinators collaborated with in-country stakeholders to guarantee the registration of eligible individuals and to ensure the receipt, handling, transportation and storage of vaccines.They also made sure that vaccine administration arrangements and communication plans were established in the country.
At both the central and local levels, emphasis was laid on working together as one unified organization, by breaking down silos across the UN entities and leveraging vari-Bull World Health Organ 2024;102:46-57| doi: http://dx.doi.org/10.2471/BLT.23.289980   Vaccinating humanitarian workers against COVID-19 Anne-Gaelle Selod et al.
ous expertise and resources.Overall, 32 UN entities 14 participated in the programme, with 31 of them entering a memorandum of understanding with the UN Secretariat.A central cost-share mechanism secured funding for the programme, thus allowing the country teams to participate with little or no impact on local budgets for their eligible populations.
Recognizing variations in local factors between countries such as the type and number of UN facilities (especially medical facilities), population size and location, the central support team developed different implementation models.In countries, territories or administrative areas with a small population served by only one UN facility, the vaccine deployment team consisted of four individuals who addressed all the components of the programme: planning, communication, pre-registration, administration, transportation and storage of the vaccine.In countries, territories or administrative areas with mediumto-large populations, often with multiple duty stations and/or served by several UN entities, communication and registration activities were centralized in one location.Meanwhile focal points from different duty stations, appointed by local vaccine deployment teams, managed the vaccination site(s), administration of vaccines, and handling and maintenance of vaccine stocks.In countries, territories and administrative areas with no UN health-care facility, the local team had to identify a medical facility and/ or contractor to administer the vaccine.
The programme used COVID-19 vaccines approved by the World Health Organization (WHO) Emergency Use Listing Procedure. 15

Vaccination strategy
Due to the limited quantity of vaccines initially made available to the programme, the central support team in conjunction with the UN Medical Directors group developed criteria to prioritize the countries, territories and administrative areas and individuals within them who would be vaccinated first.This prioritization was done using an occupational health and operational risk-based approach aligned with the World Health Organization (WHO) Strategic Advisory Group of Experts on Immunization (SAGE) roadmap for prioritizing uses of COVID-19 vaccines in the context of limited supply. 16rst, to prioritize the countries, territories and administrative areas, the working group developed a prioritization model 17 assessing countries, territories and administrative areas across six weighted health and safety parameters (Table 1).Five parameters were internal to the UN system: (i) level of access of humanitarian personnel to local UN or other health-care services; (ii) security level as defined by internal security services; (iii) COVID-19 medical evacuation rate; (iv) country mobility and hardship classification; and (v) COVID-19 case reporting rates.The external parameter was the human development index. 19Economic classifications of countries, territories and administrative areas were not included in the prioritization.Selection of the parameters was based upon a published literature review 20 that revealed the key factors for a country's lack of vaccine access, which included inadequate local public health and medical infrastructure or the collapse thereof; inadequate training of local health-care workers; and levels of conflict or violence.The group also consulted an article describing how these parameters affect a vaccine campaign. 21The central support team calculated the individual country scores through the addition of all weighted indicator metrics.The initial list contained 50 top priority countries, territories and administrative areas.After assessing the operational capacities to receive, store and administer vaccines, the central support team adapted the list to include only countries, territories and administrative areas with such capacity.
Second, to determine which humanitarian workers' groups should receive the vaccines, regardless of their duty station, the UN Medical Directors group developed an occupational health risk matrix, considering the exposure doses and frequency of different work categories.Occupational groups were classified as: high risk (high exposure dose and frequency); low risk (low exposure dose and fre-  2). 22Assessment of workers' health risks, such as age and health conditions, 16 within each group was also considered.

Target population
The central support team identified countries that had UN personnel sta-tioned in their country and had absent or low access to vaccine (Box 1).In these countries, all personnel of the 32 participating UN entities and their dependents; UN system retirees; military and police personnel deployed by the UN; key contractors; as well as nongovernmental organizations (NGOs) and other implementing partners sponsored by participating UN entities were eligible. 24 estimate the number of individuals eligible it was necessary to assess the size of UN entities operating in each country.The primary data source was records from internal security services, which had aggregate numbers of UN personnel and dependents in each country.Subsequently, as more partner organizations became eligible for participation in the programme through UN sponsorship

Data collection and recording
To identify and register eligible individuals, the central support team developed specifications for creating a cloud-based electronic record system.The programme outsourced the work of building the platform to a third-party provider.The platform included functionalities to collect and record consent forms; record risk categories from the occupational health risk matrix, as well as age and health risk factors; schedule appointments; record vaccination administration; document adverse events; and issue electronic vaccination certificates in a format consistent with WHO standards. 25The platform and the electronic certificates were in compliance with Personal Data Protection and Privacy Principles. 26uring the two years the programme was active, UN information technology personnel, part of the central support team, were responsible for adapting the platform to meet the needs of the programme throughout all its phases and to meet needs of the platform users to improve user-experience.These changes included revisions to questions such as marking them as mandatory or voluntary to submit responses to; incorporating the consent and release from liability forms into the registration rather than having them signed separately; expanding self-registration eligibility; and making all platform data visible to local coordinators.

Communication plan
The central support team created a publicly accessible website, 11 which was regularly updated to provide all relevant information, resources and guidance to personnel and local country teams.The vaccination schedule was published in advance and updated regularly on the website. 11The programme also published a document with frequently asked questions in multiple languages. 27Video interviews with UN officials and medical personnel, relayed by the network of vaccination teams, provided further information regarding the vaccination programme and its registration process, available vaccines, vaccine administration and vaccine certificates.
At every duty station, a communication focal point was responsible for the execution of the programme's communication strategy.The focal point provided local personnel and officials with a set of clear messages developed by the central support team, through emails or town hall sessions.The messages included eligibility criteria; vaccine specifics (vaccine name, type, WHO Emergency Use Listing Procedure approval); vaccine arrival timeline; and the purpose of the vaccination.The focal points also encouraged vaccination while emphasizing its voluntary nature.To ensure alignment with national programme schedules, the focal point worked closely with country health officials.The programme also organized communication events for the UN populations, where the attendants received information about programme updates, vaccine availability and any additional timely information that would raise awareness, and answer questions.

Ethical considerations
Implementation of the vaccination programme for the UN population targeted areas where supply was expected to be limited or absent.This setting led to ethical considerations on how to best protect frontline workers and partners while ensuring equitable access to the vaccine by local populations.In addition to following the WHO SAGE Roadmap, 16 the decision-makers in each location were carefully considering the progress of the national vaccine rollouts, the timing of vaccine deliveries 27

Data availability
Data can be made available upon request, subject to consideration for maintaining the anonymity of participants.

Results
In total, the programme formed 120 deployment teams tasked with vaccinating a target population of approximately 673 000 individuals across 152 countries, territories and administrative areas, including 503 255 UN individuals and 159 719 personnel from partner organizations (Fig. 1).Out of them, 20.0% (134 400 individuals) met the high-risk prioritization criteria.
In early March 2021, the programme acquired 300 000 doses of the Covishield™ vaccine (AstraZeneca, Cambridge, United Kingdom of Great Britain and Northern Ireland) manufactured by the Serum Institute of India (Pune India), from two different lots with relatively short shelf lives (20 July and 23 August 2021).Subsequently, the programme acquired the vaccines Jcovden (Janssen, Beerse, Belgium); BBIBP-CorV (Sinopharm, Shanghai, China); and Spikevax (Moderna, Cambridge, United States of America).

Administration and coverage
In the first phase, which occurred between 1 April and 31 August 2021 when COVID-19 vaccines were not readily available, 300 000 doses of the Covishield™ vaccine were delivered in over 100 shipments to 66 countries, territories and administrative areas that met the prioritization criteria.Approximately 250 000 doses of the administered doses were recorded in the cloud-based platform, while another 15 000 administered doses were manually recorded during vaccination, and later the central support team transferred these records to the platform.
The programme redistributed 38 510 excess doses from countries, territories and administrative areas with surplus vaccines to others in need between July and August 2021.Another 23 000 doses were reported to the central support team as donated or swapped for doses from other sources with longer shelf lives.
From September 2021 and onwards, the programme entered phase II when it evolved from a model seeking to provide vaccines to as many local teams as possible for primary immunization, into a model where local teams could request additional doses for any residual primary series, booster doses or variantcontaining vaccines. 28As national programmes became more robust, several local teams active in phase I suspended their participation and directed their personnel to alternate options available in their respective countries, territories and administrative areas.In the second phase, up to 1 April 2023, another 172 661 doses of different vaccine types were delivered across 38 countries, territories and administrative areas.
As of 1 April 2023, the programme has delivered over 470 000 vaccine doses to 72 countries, territories and administrative areas (Fig. 1) and 337 072 doses were recorded as administered.Out of these, 193 871 individuals have received at least one dose while 121 063 have received at least two doses of CO-VID-19 vaccine through the programme (Table 3).
The UN vaccination teams in Myanmar administered the largest number of doses through the programme (40 081 doses to 21 696 persons; Table 4).More than 67.1% (26 907) of these doses were administered to implementing partners across 260 NGOs.
Other hardship countries with high quantities of vaccines administered were, in descending order, South Sudan, Mali, Central African Republic and Democratic Republic of the Congo.In these countries, the programme vaccinated 42.2% (69 725/165 399) of the eligible population across the two-year period.At least one dose of vaccine was administered to 47 454 high-risk individuals in these four countries, which accounts for 35.3% of the 134 400 people assigned as high-risk population in the programme (Table 5).

Costs
The programme relied on resources donated by the participating UN organizations.For example, several appointed country focal points were medical professionals already employed by the UN entities, and logistics, procurement, or information technology functions were supported by existing capacities.Notably, some vaccine doses were also donated.
The programme had to seek funding of about 6 million United States dollars to cover the costs of other key elements such as additional vaccine doses; ancillary items (e.g.syringes, needles); third-party services for temperaturecontrolled vaccine storage and shipment; the cloud-based platform and salaries for a few dedicated personnel who helped running the programme.
A total of 95 (0.8%) serious adverse events were reported that either required urgent medical attention such as hospitalization, or were potentially lifethreatening or resulted in a disability. 29Among these, there were 24 instances of hospitalization (0.2%); and 51 instances of cardiac-related issues (0.4%) such as chest tightness (7; < 0.1%), heart palpitations (12; 0.1%) and chest pain (16; 0.1%).Severe adverse events were rare and, to the best of the central support team's knowledge, did not lead to any medical evacuation, permanent disability or death.

Discussion
Although the UN System-wide CO-VID-19 Vaccination Programme was able to procure a substantial number of doses, it was not enough to fully vaccinate the total eligible population.In the first phase, the programme focused on vaccinating the individuals identified as high-risk population, of which about one third of them were from four hardship countries.In the end, Vaccinating humanitarian workers against COVID-19 Anne-Gaelle Selod et al.Vaccinating humanitarian workers against COVID-19 Anne-Gaelle Selod et al.

Fig. 1. Map of eligible countries for UN COVID-19 vaccination programme
the programme was able to successfully administer about half of its allocated doses within hardship countries, and also extend access to NGO partners.
As the programme procured additional doses and vaccines became increasingly available through national vaccination efforts, other less-priority groups were able to access vaccination.The programme used internal UN parameters such as rate of medical evacuations, security and hardship classification to prioritize countries, territories and administrative areas.While this prioritization can be difficult to replicate in other contexts, our occupational health risk matrix developed to prioritize occupational groups could be applied to other occupational settings.
The seemingly low proportion of individuals vaccinated (193 871 out 673 000 eligible individuals) is an underrepresentation of the actual vaccination coverage of the eligible population for several reasons.The reporting platform only recorded doses administered through the programme and did not account for vaccinations received by eligible individuals through other efforts, to which the humanitarian workforce progressively gained more access during the study period.Vaccine hesitancy also likely played a role during the initial phase where the programme's only available vaccine was the Covishield™ vaccine.Reports of the rare but severe vaccine-induced thrombotic thrombocytopenia in healthy young individuals, 30 and reduced vaccine efficacy, 31 led several African countries to go against WHO recommendation and ban or restrict the vaccine for younger age groups, many of whom were frontline workers.The programme addressed vaccine hesitancy through a combination of vigorous internal global communication and local campaigns run by the UN country teams, highlighting vaccination benefits over risks of side-effects.][34] The programme faced logistical challenges such as short expiry dates limiting the timeline for second doses; customs clearance delays; cold chain and storage requirements; and limited internet connectivity in hardship countries, territories and administrative areas.Strategies to address these challenges included close coordination between the local vaccination teams, national authorities and senior in-country UN   35 Furthermore, the accurate tracking of the number of high-risk individuals remained challenging throughout the programme due to personnel movements, and updates to the cloud-based platform that simplified the registration as the eligibility criteria broadened in the second phase.
In the future, vaccination programmes should tailor the reporting platforms to ensure consistent recording of riskprioritization, even as the eligibility might expand.The wastage of vaccine was reasonable, estimated at no more than 5% in the first phase, and well within forecast rates of 10% and the wastage rates of up to 30% reported by other vaccination campaigns. 36As for the second phase, the wastage rate is yet to be determined, as the programme continues to hold an inventory of unexpired vaccines.
The UN and other organizational entities regularly conduct local vaccination drives for their personnel, but also roll out exceptional distribution of supplies or vaccinations during outbreaks, such as personal protective equipment during Ebola virus disease outbreaks and cholera vaccines.Based on our experiences, a model for largescale operations can be developed to efficiently manage emergency health aid and immunization campaigns across multiple countries, territories and administrative areas.This model would integrate routine and endemic disease vaccines, particularly in regions where local procurement is challenging. 37n conclusion, the programme has been contributing to protecting the frontline humanitarian workforce and peacekeepers in the context of an exceptional global health emergency, and enabling them to continue delivering on their critical mandates to protect, serve and save others.The model was quickly developed with no pre-established protocol and enabled rapid distribution and administration of vaccines across the world, especially in hardship countries, territories and administrative areas.The programme's success can be attributed to its twolevel operational structure, rigorous risk-based prioritization approach, flexible logistic and vaccine administration model, collaborative use of in-house experts and close coordination across various UN entities.The programme provides an example of working together as One UN across entities on both a global and local scale.

Table 2 . Risk of COVID-19 through occupational exposure by humanitarian workers' activities Description SAGE priority category 16 Exposure dose level Exposure frequency level Overall risk Examples of roles Contact with people or fluids with known, suspected or possible COVID-19
: SAGE priorities categories are: Ia: Stage Ia includes health workers at high or very high risk of acquiring and transmitting infection; II: Stage II includes health workers engaged in immunization delivery; and III: Stage III includes social or employment groups at elevated risk of acquiring and transmitting infection.Vaccinating humanitarian workers against COVID-19 Anne-Gaelle Selod et al.
16VID-19: coronavirus disease 2019; NA: not applicable; SAGE: Strategic Advisory Group of Experts on Immunization.aMedicalevacuation is the urgent transportation of an ill individual to another country when essential care or treatment cannot be provided locally due to inadequate medical facilities.Note16Bull World Health Organ 2024;102:46-57| doi: http://dx.doi.org/10.2471/BLT.23.289980

Table 3 . Cumulative number of individuals who have received COVID-19 vaccine through the UN system-wide COVID-19 Vaccination Programme, 1 April 2023 Eligible group, by country income classification No. of people vaccinated Total no. of doses administered One dose Two doses Three doses Four doses Five doses Total Low-income countries, territories and administrative areas
23VID-19: coronavirus disease 2019; NGO: nongovernmental organization; UN: United Nations.aIndividualsmovinglocation and/or economic classification was not applicable to location.Note: Countries, territories and administrative areas were classified according to the World Bank economic classification.23BullWorldHealth Organ 2024;102:46-57| doi: http://dx.doi.org/10.2471/BLT.23.289980

Table 5 . Low-income hardship countries with the greatest number of delivered and administered doses from the UN COVID-19 vaccination programme, as of 1 April 2023 Country Prioritization rank a No. of doses delivered b No. of doses administered b (% of doses administered globally) c Eligible population at the start of phase I, d no. Vaccinated eligible population, b no. (%) e High-risk individuals vaccinated during phase I f
The UN COVID-19 vaccination programme administered a total of 337 072 doses as of 1 April 2023.dEligiblepopulationsize was estimated during the programme's set up and was not updated further to reflect any changes in personnel size.eThepercentagesshow the total vaccinated population over phase I and II to the eligible population reported at the start of phase I.The actual vaccinated population may be greater as the cloud-based platform only recorded doses administered through the programme and did not track individuals if they received doses from national programmes.fVaccinated with at least one dose.Bull World Health Organ 2024;102:46-57| doi: http://dx.doi.org/10.2471/BLT.23.289980 a Prioritization ranking of countries is based on criteria presented in Table1.b Includes phase I and II.c